NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 11: Area Related To Circles - Exercise 11.4

Question 8

Step 1: Recall the formula for the area of a sector when the arc length is given:

\[ A = \tfrac{1}{2} \times r \times l \]

Here, \(r\) = radius of the circle, and \(l\) = arc length.

Step 2: Write down the values from the question:

• Radius, \(r = 5\,\text{cm}\)
• Arc length, \(l = 3.5\,\text{cm}\)

Step 3: Substitute these values into the formula:

\[ A = \tfrac{1}{2} \times 5 \times 3.5 \]

Step 4: First multiply radius and arc length:

\[ 5 \times 3.5 = 17.5 \]

Step 5: Now divide by 2:

\[ \tfrac{17.5}{2} = 8.75 \]

Final Answer: \(A = 8.75\,\text{cm}^2\)

So, the area of the sector is 8.75 square centimetres.